* nix/nix-daemon/guix-daemon.cc (GUIX_OPT_NO_BUILD_HOOK): New macro.
(options): Add '--no-build-hook'.
(parse_opt): Handle it.
(main)[HAVE_DAEMON_OFFLOAD_HOOK]: Set 'useBuildHook' by default.
Set $NIX_BUILD_HOOK to our offload hook unless otherwise specified.
[!HAVE_DAEMON_OFFLOAD_HOOK]: Clear 'useBuildHook'.
* pre-inst-env.in: Set and export NIX_BUILD_HOOK.
* nix/scripts/offload.in, guix/scripts/offload.scm: New files.
* guix/ui.scm (show-guix-help)[internal?]: Add "offload".
* config-daemon.ac: Call 'GUIX_CHECK_UNBUFFERED_CBIP'.
Instantiate 'nix/scripts/offload'. Set 'BUILD_DAEMON_OFFLOAD'
conditional, and optionally define 'HAVE_DEAMON_OFFLOAD_HOOK' cpp
macro.
* daemon.am (nodist_pkglibexec_SCRIPTS)[BUILD_DAEMON_OFFLOAD]: Add it.
* Makefile.am (MODULES)[BUILD_DAEMON_OFFLOAD]: Add
'guix/scripts/offload.scm'.
(EXTRA_DIST)[!BUILD_DAEMON_OFFLOAD]: Likewise.
* m4/guix.m4 (GUIX_CHECK_UNBUFFERED_CBIP): New macro.
* doc/guix.texi (Setting Up the Daemon): Move most of the body to...
(Build Environment Setup): ... this. New subsection.
(Daemon Offload Setup): New subsection.
* srfi/srfi-37.scm.in: New file, taken from Guile 2.0.9.
* m4/guix.m4: New macro.
* configure.ac: Use it. Define Automake conditional `INSTALL_SRFI_37'.
* Makefile.am (nobase_nodist_guilemodule_DATA)[INSTALL_SRFI_37]: Add
srfi/srfi-37.scm.
(GOBJECTS)[INSTALL_SRFI_37]: Add srfi/srfi-37.go.
(srfi/srfi-37.scm)[INSTALL_SRFI_37]: New target.
(EXTRA_DIST): Add srfi/srfi-37.scm.in.
* configure.ac: Compute and substitute `guix_localstatedir'.
* m4/guix.m4: Substitute `guix_system'.
* guix/config.scm.in (%store-directory, %store-directory, %system): New
variables.
* guix/store.scm (%nix-state-dir): Remove.
(%default-socket-path): Use %STATE-DIRECTORY as the default.
(%store-prefix): Use %STORE-DIRECTORY as the default.
* guix/utils.scm (%current-system): Default to %SYSTEM.
